A Cellular Approach to a Biomarker of Aging

Researchers here discuss a new cellular approach to building a biomarker of aging, a way to assess the biological age of an individual. In the SENS view of aging as accumulated molecular damage and its secondary consequences, such a biomarker must reflect the current load of damage present in an individual: people with more damage are older and suffer greater degeneration. The true value of a good biomarker of biological age is that it can be used to significantly speed up research and development, in that it will allow potential rejuvenation therapies to be assessed for their ability to turn back aging far more rapidly, cost-effectively, and accurately than is presently the case.

Sure, you know how old you are, but what about your cells? Are they the same age? Are they older, younger? Why does it matter? A team of researchers is reporting progress in developing a method to accurately determine the functional age of cells, a step that could eventually help clinicians evaluate and recommend ways to delay some health effects of aging and potentially improve other treatments, including skin graft matching and predicting prospects for wound healing.

The researchers devised a system that can consider a wide array of cellular and molecular factors in one comprehensive aging study. These results show that the biophysical qualities of cells, such as cell movements and structural features, make better measures of functional age than other factors, including cell secretions and cell energy. The team examined dermal cells from just underneath the surface of the skin taken from both males and females between the ages of 2 to 96 years. The researchers hoped to build a system that through computational analysis could take the measure of various factors of cellular and molecular functions. From that information, they hoped to determine the biological age of individuals more accurately using their cells, in contrast to previous studies, which makes use of gross physiology, or examining cellular mechanisms such as DNA methylation.

Researchers trying to understand aging have up to now focused on factors such as tissue and organ function and on molecular-level studies of genetics and epigenetics, meaning heritable traits that are not traced to DNA. However, the level in between, the cells, have received relatively little attention. This research was meant to correct for that omission by considering also the biophysical attributes of cells, including such factors as the cells' ability to move, maintain flexibility and structure. This focus emerges from the understanding that changes associated with aging at the physiological level such as diminished lung capacity, grip strength and mean pressure in the arteries "tend to be secondary to changes in the cells themselves, thus advocating the value of cell-based technologies to assess biological age." For example, older cells are more rigid and do not move as well as younger cells, which most likely contributes to the slower wound healing commonly seen in older people.

From the analysis, researchers were able to stratify individuals' samples into three groups: those whose cells roughly reflected their chronological age, those whose cells were functionally older, and those whose cells were functionally younger. The results also showed that the so-called biophysical factors of cells determined a more accurate measure of age relative to biomolecular factors such as cell secretions, cell energy, and the organization of DNA. The more accurate system could eventually enable clinicians to see aging in the cells before the person experiences age-related health decline. This in turn could allow doctors to recommend treatments or changes in life habits, such as exercise or diet changes.